Epidemiological and experimental studies suggest that a proper diet and a healthy life style can decrease the risk of cancer by up to 70%. The cancers most closely related to nutrition are breast and endometrial cancers in women and prostate and gastrointestinal cancers in men. The review outlines that many anti-oxidants, vitamins, phytochemicals, and other micronutrients in food have cancer preventing effects, while many food additives, pesticide residues and high consumption of charbroiled meat, nitrites, salt, animal fat and trans fatty acids have been associated with increased cancer risk. Most studies with micronutrients in relation to cancer have been conducted with individual compounds. In contrast, our in vitro and in vivo research utilizing over 50 human cancer cell lines demonstrated better anti-cancer efficacy with a synergistic combination of micronutrients rather than individual compounds. Pleiotropic effects of a nutrient combination have been demonstrated in cancer preventive and also in therapeutic aspects by inhibiting the hallmarks of cancer, including its growth, invasion and metastasis. Dietary approaches to health need to be further explored as being non-toxic, generally well tolerated, and without significant side effects that are commonly associated with conventional chemotherapy and radiation therapy.